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Diffstat (limited to 'include/libavutil/rational.h')
-rw-r--r-- | include/libavutil/rational.h | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/include/libavutil/rational.h b/include/libavutil/rational.h new file mode 100644 index 00000000..4d91f7ba --- /dev/null +++ b/include/libavutil/rational.h @@ -0,0 +1,129 @@ +/* + * rational numbers + * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at> + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +/** + * @file + * rational numbers + * @author Michael Niedermayer <michaelni@gmx.at> + */ + +#ifndef AVUTIL_RATIONAL_H +#define AVUTIL_RATIONAL_H + +#include <stdint.h> +#include "attributes.h" + +/** + * rational number numerator/denominator + */ +typedef struct AVRational{ + int num; ///< numerator + int den; ///< denominator +} AVRational; + +/** + * Compares two rationals. + * @param a first rational + * @param b second rational + * @return 0 if a==b, 1 if a>b and -1 if a<b + */ +static inline int av_cmp_q(AVRational a, AVRational b){ + const int64_t tmp= a.num * (int64_t)b.den - b.num * (int64_t)a.den; + + if(tmp) return (tmp>>63)|1; + else return 0; +} + +/** + * Converts rational to double. + * @param a rational to convert + * @return (double) a + */ +static inline double av_q2d(AVRational a){ + return a.num / (double) a.den; +} + +/** + * Reduces a fraction. + * This is useful for framerate calculations. + * @param dst_num destination numerator + * @param dst_den destination denominator + * @param num source numerator + * @param den source denominator + * @param max the maximum allowed for dst_num & dst_den + * @return 1 if exact, 0 otherwise + */ +int av_reduce(int *dst_num, int *dst_den, int64_t num, int64_t den, int64_t max); + +/** + * Multiplies two rationals. + * @param b first rational + * @param c second rational + * @return b*c + */ +AVRational av_mul_q(AVRational b, AVRational c) av_const; + +/** + * Divides one rational by another. + * @param b first rational + * @param c second rational + * @return b/c + */ +AVRational av_div_q(AVRational b, AVRational c) av_const; + +/** + * Adds two rationals. + * @param b first rational + * @param c second rational + * @return b+c + */ +AVRational av_add_q(AVRational b, AVRational c) av_const; + +/** + * Subtracts one rational from another. + * @param b first rational + * @param c second rational + * @return b-c + */ +AVRational av_sub_q(AVRational b, AVRational c) av_const; + +/** + * Converts a double precision floating point number to a rational. + * @param d double to convert + * @param max the maximum allowed numerator and denominator + * @return (AVRational) d + */ +AVRational av_d2q(double d, int max) av_const; + +/** + * @return 1 if q1 is nearer to q than q2, -1 if q2 is nearer + * than q1, 0 if they have the same distance. + */ +int av_nearer_q(AVRational q, AVRational q1, AVRational q2); + +/** + * Finds the nearest value in q_list to q. + * @param q_list an array of rationals terminated by {0, 0} + * @return the index of the nearest value found in the array + */ +int av_find_nearest_q_idx(AVRational q, const AVRational* q_list); + +#endif /* AVUTIL_RATIONAL_H */ |